Google’s “Project Svelte” optimizes Android 4.4 to be compatible with devices that have as little as 512MB of RAM. Ideally, this means low-end devices will have the opportunity to update to KitKat as well.

Note that these are for specific model numbers and that timelines are not listed. We should hope that Samsung makes some formal announcements for these, and variations in the near term. Assuming the list is accurate, of course.